JP2005081485A - High temperature mechano-chemical polishing method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high temperature mechano-chemical polishing method and a device, mechano-chemically polishing a work piece at a high temperature in an open atmosphere, facilitating approach to a work piece in the process of polishing, a polishing plate and abrasive grains, having high workability, and remarkably heightening the machining efficiency. <P>SOLUTION: The work piece 1 is held by two flat plates (a polishing plate 12 and a work holding plate 16), one or both of the flat plates are heated to raise the temperature of the work piece, and while fine particles 2 causing mechano-chemical action are supplied between the work piece and at least one flat plate, the work piece is mechano-chemically polished at a high temperatures. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a high temperature mechanochemical polishing method and apparatus for performing mechanochemical polishing at high temperature in an open atmosphere.

  In recent years, the need for high-quality polishing of sapphire and ceramic materials has increased rapidly. Sapphire is used for thermal filters such as blue laser substrates, electronic devices such as SOS, and liquid crystal projectors. In addition, silicon nitride and silicon carbide ceramics are expected as next-generation high-performance substrate materials.

Sapphire and ceramic materials are extremely hard and are known as difficult-to-process materials. Therefore, polishing of these hard difficult-to-process materials is performed by room temperature wet polishing using a processing liquid having a chemical corrosive action.
However, the polishing rate of room temperature wet polishing is extremely low, and it has been forced to work for a long time of several hours to several tens of hours for the final polishing in the polishing process, which has been a factor in poor productivity and high manufacturing cost. .

Therefore, the MCP (Mechanochemical Polishing) method, which creates a high-quality surface by inducing a chemical reaction by friction with hard hard-to-work materials such as sapphire using soft abrasive grains such as SiO ₂ , is Tokai University. Have been studied by Professor Yasunaga et al.

Yasuo Yasunaga et al., Research on the effect of interfacial solid-phase reaction on wear and its application to precision processing, Electronic Technology Research Institute Report No. 776, Electronic Technology Research Institute, December 1977 Yasuo Yasunaga, mechanochemical polishing with soft abrasive grains, optical technology contact, Vol. 31. No. 10 (1993) Yasuo Yasunaga, Special Polishing Technology, Machines and Tools, May 1998

  According to the mechanochemical polishing method described above, it has been confirmed that, for example, the processing rate of one digit or more is increased by raising the temperature of the processing atmosphere to about 500 ° C.

  However, conventionally, in order to perform mechanochemical polishing (mechanochemical polishing) at a high temperature, as illustrated in FIG. 9, the entire region where the hard difficult-to-work material (workpiece) is mechanochemically polished is stored in a container, The inside of the container had to be heated with a heater or the like to increase the ambient temperature. As a result, conventionally, it is difficult to approach the workpiece, polishing plate, and abrasive grains being polished, the workability is low, and the processing efficiency cannot be sufficiently increased.

  The present invention has been made to solve such problems. That is, the object of the present invention is that the workpiece can be mechanochemically polished at a high temperature in an open atmosphere, the approach to the workpiece, polishing plate, and abrasive grains being polished is easy, workability is high, and processing efficiency is improved. It is an object of the present invention to provide a high temperature mechanochemical polishing method and apparatus which can be greatly improved.

  According to the present invention, a workpiece is sandwiched between two flat plates, one or both of the flat plates are heated to raise the temperature of the workpiece, and fine particles that cause mechanochemical action are supplied between the workpiece and at least one of the flat plates. There is provided a high temperature mechanochemical polishing method characterized in that a workpiece is mechanochemically polished at a high temperature.

According to the method of the present invention, since the workpiece is sandwiched between two flat plates heated on one or both, the two flat plates and the workpiece and fine particles located between them are also substantially transferred by heat transfer. At the same temperature.
Therefore, the work can be mechanochemically polished at a high temperature while supplying fine particles that produce a mechanochemical action in an open atmosphere without containing a hard difficult-to-process material (work) in the container. The approach to the polishing plate and the abrasive grains is easy, the workability is high, and the processing efficiency can be greatly increased.

  Further, according to the present invention, a polishing plate having a horizontal polishing surface, a plate turning device for horizontally driving the polishing plate about a vertical axis ZZ, a work holding plate for holding a work, A workpiece sliding device for sliding the workpiece along the polishing surface while urging the workpiece holding plate toward the polishing surface, and a heating device for heating the polishing plate and / or the workpiece holding plate. There is provided a high-temperature mechanochemical polishing apparatus characterized in that a workpiece is subjected to mechanochemical polishing at a high temperature while supplying fine particles generating a mechanochemical action between the polishing plate and the polishing plate.

According to the configuration of the present invention, since the polishing plate and / or the work holding plate is heated by the heating device, the work is sandwiched between the heated polishing plate and the work holding plate. Fine particles can also be heated to substantially the same temperature by heat transfer.
Therefore, the work can be mechanochemically polished at a high temperature while supplying fine particles that produce a mechanochemical action in an open atmosphere without containing a hard difficult-to-process material (work) in the container. The approach to the polishing plate and the abrasive grains is easy, the workability is high, and the processing efficiency can be greatly increased.

  According to a preferred embodiment of the present invention, the heating device includes a hot plate that is fixed in close contact with the back surface of the polishing plate and includes a heater element therein, a temperature detector that measures the temperature in the hot plate, A rotating shaft having one end connected to the hot plate and extending along the axis ZZ, a slip ring for taking out the power line and the signal line from the rotating shaft to a fixed portion, and the hot plate and the temperature detector via the slip ring And a temperature control device for controlling the connected hot plate to a predetermined temperature suitable for mechanochemical polishing.

With this configuration, power can be supplied to the heater element in the hot plate via the slip ring to raise the temperature of the hot plate itself, and the polishing plate fixed in close contact by heat transfer (heat conduction) can be heated. .
In addition, the temperature in the hot plate is measured with a temperature detector, and the electric power supplied to the heater element is controlled by the temperature control device via the slip ring to bring the hot plate and the polishing plate to a predetermined temperature suitable for mechanochemical polishing. Can be controlled.

  The plate turning device has a through-hole through which the rotating shaft passes and supports a hot plate so that the hot plate can rotate horizontally around the axis ZZ, and the rotation axis is connected to the axis ZZ. And a turning drive device that rotates around the center.

With this configuration, the heating device can be controlled separately from the plate turning device by passing the rotating shaft of the heating device through the through hole of the turning shaft and attaching the slip ring to the lower end thereof.
In addition, the hot plate of the heating device is fixed to the rotating shaft, and the hot plate is fixed in close contact with the back surface of the polishing plate, so that the polishing plate is placed horizontally around the vertical axis ZZ through the hot plate. It can be rotated.

  The workpiece sliding device includes a workpiece pivoting device that rotates the workpiece holding plate horizontally around an axis Z′-Z ′ parallel to the axis ZZ, and the workpiece pivoting device is used as a polishing surface. It consists of a workpiece urging device that urges the workpiece toward and a horizontal movement device that horizontally moves the workpiece holding plate along the polishing surface.

  With this configuration, while the work is urged toward the polishing surface, the work is rotated horizontally around an axis Z′-Z ′ parallel to the axis ZZ, and horizontally along the polishing surface. The entire surface of the work can be evenly mechanochemically polished.

The workpiece holding plate is a vacuum chuck.
With this configuration, the workpiece can be reliably held even at high temperatures.

  As described above, according to the high temperature mechanochemical polishing method and apparatus of the present invention, a workpiece can be mechanochemically polished at a high temperature in an open atmosphere, and the workpiece, polishing plate, and abrasive grains being polished can be easily approached. Therefore, the workability is high and the processing efficiency can be greatly increased.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is an overall configuration diagram of a high-temperature mechanochemical polishing apparatus according to the present invention. As shown in this figure, the high-temperature mechanochemical polishing apparatus 10 of the present invention includes a polishing plate 12, a plate turning device 14, a workpiece holding plate 16, a workpiece sliding device 18, and a heating device 30, and the workpiece 1 and the polishing plate. The workpiece 1 is mechanochemically polished at a high temperature while supplying fine particles 2 that generate a mechanochemical action between the two.

The workpiece 1 is preferably a hard difficult-to-work material such as sapphire or a ceramic material, but the present invention is not limited to this and can be applied to other materials such as silicon and glass materials. Further, the shape of the workpiece 1 is preferably a thin disk shape such as a wafer, but the present invention is not limited to this, and may be a small member having a small heat capacity.
As the fine particles 2 that cause a mechanochemical action, well-known particles such as SiO ₂ , iron oxide, MgO can be used. The particle size distribution of the fine particles 2 is arbitrarily set in accordance with the material of the work 1, the required surface roughness, and the like.

  In this example, the polishing plate 12 is a thick flat plate whose upper surface is a horizontal polishing surface 12a. The polishing plate 12 is made of a material having high wear resistance and high thermal conductivity, such as copper, copper alloy, steel, ceramics, and the like. The back surface of the polishing plate 12 is fixed in close contact with the upper surface of the hot plate 32 with a bolt or the like as will be described later, and is heated by heat conduction from the hot plate 32 while rotating together with the hot plate 32.

FIG. 2 is a partial configuration diagram of FIG. In this figure, the heating device 30 includes a hot plate 32, a temperature detector 34, a rotating shaft 36, a slip ring 38, and a temperature control device 40.
The hot plate 32 includes a main plate 32a and a heater plate 32b that are attached to each other with bolts or the like. The main plate 32a is in close contact with the back surface (the lower surface in this example) of the polishing plate 12 and fixed with bolts or the like. The heater plate 32b incorporates a plurality (five in this example) of heater elements 31 in a groove provided therein, so that the entire hot plate is heated uniformly.
For example, the plurality of heater elements 31 may be circular heater elements having different diameters, and these heater elements 31 may be arranged concentrically and in a plane.

The temperature detector 34 is, for example, a thermocouple, and its measurement point 34a is positioned at an intermediate position between the plurality of heater elements 31 so as to detect the representative temperature of the entire hot plate.
The rotary shaft 36 has one end (the upper end in this example) connected to the hot plate 32 and extends downward through the slip ring 38 along the axis ZZ. The slip ring 38 takes out the power line 31 a and the signal line 34 b from the rotating shaft 36 to a fixed portion, and is connected to the temperature control device 40. The temperature control device 40 is connected to the temperature detector 34 and the heater element 31 in the hot plate 32 via the slip ring 38, and controls the entire hot plate to a predetermined temperature suitable for mechanochemical polishing. .

With the above-described configuration, the polishing plate 12 is fixed in close contact by heat transfer (heat conduction) by supplying electric power to the heater element 31 in the hot plate 32 through the slip ring 38 to raise the temperature of the hot plate itself. Can be heated.
Further, the temperature in the hot plate 32 is measured by the temperature detector 34, and the power supplied to the heater element 31 is controlled by the temperature control device 40 through the slip ring 38 to control the hot plate 32 and the polishing plate attached thereto. 12 can be controlled to a predetermined temperature suitable for mechanochemical polishing.

  A heating device having a similar configuration may be provided in the workpiece sliding device 18 to heat the workpiece holding plate 16.

In FIG. 1, the plate turning device 14 includes a turning shaft 14 a that supports a hot plate 32 so as to be horizontally rotatable around a shaft center ZZ by a bearing 14 b, and a turning drive device 15. The turning shaft 14a has a through hole through which the rotating shaft 32 of the heating device 30 passes, and the rotating shaft 36 is connected to the lower slip ring 38 through the through hole.
The turning drive unit 15 includes an electric motor 15a with a speed reducer, pulleys 15b and 15c, and a timing belt 15d. The turning drive unit 15 rotates the turning shaft 14a around the axis ZZ, and the polishing plate 12 has a vertical axis Z-. It is driven to rotate horizontally around Z.

With this configuration, the heating device 30 can be controlled separately from the plate turning device 14 by passing the rotating shaft 32 of the heating device 30 through the through hole of the turning shaft 14 a and attaching the slip ring 38 to the lower end thereof.
Further, the hot plate 32 of the heating device 30 is fixed to the turning shaft 14a, and the hot plate 32 is fixed in close contact with the back surface of the polishing plate 12, so that the polishing plate 12 is vertically centered Z through the hot plate 32. -It can be rotated horizontally around Z.

  In this example, the work holding plate 16 is a vacuum chuck, and is connected to a suction device (not shown) via a suction line 17 extending along an axis Z′-Z ′ parallel to the axis ZZ. By attracting and holding upward in the figure, the workpiece 1 is reliably held even at high temperatures.

The work sliding device 18 includes a work turning device 22, a work urging device 24, and a horizontal movement device 26.
The work swiveling device 22 has a work holding plate 16 attached to the lower end thereof, a rotating shaft 22a supported so as to be horizontally rotatable around an axis Z′-Z ′ parallel to the axis ZZ, and an electric motor with a speed reducer. 22b, pulleys 22c and 22d, and timing belt 22e. The work holding plate 16 is horizontally driven around an axis Z′-Z ′ parallel to the axis ZZ.

The work urging device 24 includes a guide rail 24 a that guides the work swiveling device 22 so as to be movable up and down, and a pneumatic cylinder 24 b that moves the work swiveling device 22 in the vertical direction. 1 is biased toward the polishing surface 12a.
In this example, the horizontal moving device 26 includes a guide rail 26a that guides the work urging device 24 so as to be horizontally movable, a ball screw 26b that horizontally moves the work urging device 24, and a drive device 26c that rotationally drives the ball screw 26b. The workpiece 1 is moved horizontally along the polishing surface 12a together with the workpiece holding plate 16. The driving device 26c includes, for example, an electric motor with a reduction gear, a pulley, and a timing belt.

  With the above-described configuration, the work surface 1 is urged toward the polishing surface 12a, and the work surface 1 is driven to rotate horizontally about an axis Z'-Z 'parallel to the axis ZZ while being polished. The entire surface of the workpiece can be evenly mechanochemically polished by moving horizontally along 12a.

According to the configuration of the present invention described above, since the polishing plate 12 and / or the workpiece holding plate 16 are heated by the heating device 30, the workpiece 1 is sandwiched between the heated polishing plate 12 and the workpiece holding plate 16. The workpiece 1 and the fine particles 2 having a small heat capacity located between them can also be heated to substantially the same temperature by heat transfer.
Accordingly, the work 1 can be mechanochemically polished at a high temperature while supplying fine particles 2 that cause a mechanochemical action in an open atmosphere without containing the hard difficult-to-process material (work 1) in the container. The workpiece, the polishing plate, and the abrasive grains can be easily approached, the workability is high, and the processing efficiency can be greatly increased.

  In the method of the present invention, the workpiece 1 is sandwiched between two flat plates (in this example, the polishing plate 12 and the workpiece holding plate 16), and one or both of the polishing plate 12 and the workpiece holding plate 16 are heated to remove the workpiece 1. The temperature of the workpiece 1 is mechanochemically polished at a high temperature while supplying fine particles 2 that cause a mechanochemical action between the workpiece 1 and at least one flat plate (for example, the polishing plate 12).

According to this method, since the workpiece 1 is sandwiched between two flat plates heated on one or both, the two flat plates and the workpiece having a small heat capacity and the fine particles 2 are also substantially transferred by heat transfer. At the same temperature.
Therefore, the work can be mechanochemically polished at a high temperature while supplying fine particles that produce a mechanochemical action in an open atmosphere without containing a hard difficult-to-process material (work) in the container. The approach to the polishing plate and the abrasive grains is easy, the workability is high, and the processing efficiency can be greatly increased.

Examples of the present invention will be described below. The high-temperature mechanochemical polishing apparatus 10 of the present invention shown in FIG. 1 was actually manufactured. The specifications are as follows.
(1) Lap pressure: Air control (2) Work: Forced drive by motor, motor single-phase AC100V, 200W, work size φ100mm, rotation speed 160min ⁻¹ , applied pressure 1.0-300N
(3) Workpiece attachment part: Adhesion method or vacuum chuck method (4) Lap surface plate (polishing plate): Built-in plate footer (rotary heater), motor single-phase AC100V, 200W, size φ250mm, rotation speed 160min- ¹
(5) Plate hotter (rotating heater): operating temperature about 500 ° C, heater size φ150mm
(6) Dimensions / weight: W400 × L720 × H1100 Approx. 100kg

  FIG. 3 is a diagram showing the high temperature hardness of various substances. As shown in this figure, hard difficult-to-work materials such as sapphire, quartz glass, and iron oxide (FeO) generally have a characteristic that the Vickers hardness decreases as the temperature increases.

  FIG. 4 is a diagram showing the general characteristics of the mechano polishing method using soft particles. The machining mode of the mechano polishing method is almost the same as that of normal lapping polishing, but differs in that powder that is mechanically softer than the workpiece and can cause a solid phase reaction with the workpiece surface is used as the abrasive grains.

FIG. 5 is a model diagram showing contact points between the soft particles and the workpiece. In the mechano polishing method, high-temperature and high-pressure are generated by frictional energy at the contact point local area between the soft particles and the workpiece, and both solid-phase reactions occur within a minute contact time. Polishing proceeds by being removed in minute units.
Therefore, unlike mechanical polishing with conventional hard abrasive grains, the particles acting as abrasive grains are mechanically soft, so the particle side is deformed at the contact point, and scratches or work-affected layers based on the indentation / scratching action of the particles Will not occur.

FIG. 6 is a diagram showing the relationship between the atmospheric temperature and the processing amount. This figure shows high temperature polishing of sapphire in a nitrogen atmosphere using α-Fe ₂ O ₃ particles and SiC particles. From this result, in mechanochemical polishing with α-Fe ₂ O ₃ , the processing amount at 500 ° C. is more than 10 times that at room temperature, and the apparatus of the present invention can achieve the same or higher effect. It is shown that.

FIG. 7 is a diagram comparing high-temperature polishing using auto-oxidation of a steel polisher and wet polishing using α-Fe ₂ O ₃ particles. From this figure, it can be seen that at 400 to 500 ° C. where α-Fe ₂ O ₃ and Fe ₃ O ₄ are produced, a larger processing amount than wet polishing with α-Fe ₂ O ₃ particles can be obtained.

FIG. 8 is a diagram comparing the amount of sapphire processed by various powders, dry and wet. As shown in this figure, SiO ₂ and α-Fe ₂ O ₃ particles exhibiting a mechanochemical effect are particularly dry and exhibit high processing efficiency.

As described above, MCP (Mechanochemical Polishing) method was studied by Prof. Yasunaga et al. Of Tokai University by inducing a chemical reaction by friction between particles such as SiO ₂ and sapphire. It has been confirmed that the processing rate of one digit or more is increased by raising the temperature of the steel to about 500 ° C.
In addition, the present invention has proposed a new polishing apparatus that enables MCP in an open atmosphere by increasing the temperature of the polishing plate according to the present invention. This apparatus has a feature that the temperature of the workpiece can be raised safely and efficiently by concentrating the heating on the processing point. Moreover, the outstanding effect of the dry grinding | polishing by a bengara at 400-500 degreeC has been confirmed.
Furthermore, applications of single crystal SiC are advancing as advanced semiconductor device substrates, but application of MCP is considered to be effective as in sapphire.

Further, the apparatus of the present invention has sufficient practicality and effectiveness as a final polishing method particularly for difficult-to-process materials that require a long time in conventional room temperature wet polishing.
That is, the apparatus of the present invention is a polishing apparatus that is used in a rotating disk type normal polishing method, but has a feature that dry polishing can also be performed in a high temperature environment of normal temperature to 500 ° C. in an air atmosphere.

  According to the mechanochemical polishing method (MCP), any difficult-to-process material having ultra-high hardness can be polished using a soft abrasive grain or a polishing plate suitable for each, without causing a work-affected layer. it can. In the MCP method, polishing proceeds based on a direct chemical reaction (solid phase reaction) at a minute contact point with an abrasive grain or a polishing plate. Since the reaction rate of the chemical reaction generally increases as the temperature increases, it is expected that the polishing ability of the MCP also increases as the temperature increases. Therefore, for example, what conventionally required 10 hours or more of room temperature wet polishing of sapphire with a colloidal silica abrasive can be completed in a few tens of minutes or less using this developed apparatus. Even if it takes some time for the temperature rise and cooling of the polishing apparatus, if the apparatus configuration is such that the polishing sample can be continuously loaded and unloaded, the processing efficiency can be improved by one digit or more.

  The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the invention.

1 is an overall configuration diagram of a high-temperature mechanochemical polishing apparatus of the present invention. FIG. 2 is a partial configuration diagram of FIG. 1. It is a figure which shows the high temperature hardness of various substances. It is a figure which shows the general characteristic of the mechano polishing method by a soft particle. It is a model figure which shows the contact point of a soft particle and a workpiece. It is a figure which shows the relationship between atmospheric temperature and a processing amount. And hot polishing utilizing autoxidation of the steel polisher, shows a comparison of a wet polishing by particles of α-Fe ₂ O _3. It is the figure which compared the amount of sapphire processing by various powders with a dry type and a wet type. It is the schematic of the conventional sealed high temperature mechanochemical polishing apparatus.

Explanation of symbols

1 work, 2 fine particles,
10 high temperature mechanochemical polishing equipment, 12 polishing plate,
14 plate turning device, 14a turning shaft,
15 slewing drive, 15a electric motor,
15b, 15c pulley, 15d timing belt,
16 workpiece holding plate, 17 suction line, 18 workpiece sliding device,
22 work turning device, 22a rotating shaft, 22b electric motor,
22c, 22d pulley, 22e timing belt,
24 work biasing device, 26 horizontal movement device,
26a guide rail, 26b ball screw, 26c driving device,
30 heating device, 31 heater element, 32 hot plate,
32a main plate, 32b heater plate,
34 temperature detector, 34a measuring point, 36 rotation axis,
38 slip ring, 40 temperature control device

Claims (6)

The workpiece is sandwiched between two flat plates, one or both of the flat plates are heated to raise the temperature of the workpiece, and the workpiece is mechanized at a high temperature while supplying fine particles that cause mechanochemical action between the workpiece and at least one of the flat plates. A high-temperature mechanochemical polishing method characterized by chemical polishing. A polishing plate having a horizontal polishing surface, a plate turning device that rotates the polishing plate horizontally about a vertical axis ZZ, a workpiece holder that holds a workpiece, and polishing the workpiece holder A work sliding device that slides the work along the polishing surface while being biased toward the surface, and a heating device that heats the polishing plate and / or the work holder, and a mechanochemical between the work and the polishing plate A high temperature mechanochemical polishing apparatus characterized in that a workpiece is mechanochemically polished at a high temperature while supplying fine particles that cause an action. The heating device includes a hot plate that is fixed in close contact with the back surface of the polishing plate and includes a heater element therein, a temperature detector that measures the temperature in the hot plate, and one end connected to the hot plate. Suitable for mechanochemical polishing, rotating shaft extending along -Z, slip ring for extracting power line and signal line from the rotating shaft to the fixed part, and connecting to hot plate and temperature detector via the slip ring The high-temperature mechanochemical polishing apparatus according to claim 2, further comprising a temperature control device that controls the temperature to a predetermined temperature. The plate turning device includes a turning shaft that has a through hole through which the rotating shaft passes and supports a hot plate so as to be horizontally rotatable around the axis ZZ, and the turning axis around the axis ZZ. The high-temperature mechanochemical polishing apparatus according to claim 3, further comprising a turning drive device that rotates. The workpiece sliding device includes: a workpiece pivoting device that rotates the workpiece holder horizontally around an axis Z′-Z ′ parallel to the axis ZZ; and the workpiece pivoting device facing the polishing surface. The high-temperature mechanochemical polishing apparatus according to claim 2, comprising a work urging device for urging and a horizontal movement device for horizontally moving the work holder along the polishing surface. The high-temperature mechanochemical polishing apparatus according to claim 2, wherein the work holder is a vacuum chuck.

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